- - RIGHT MAIN no sound?
(http://www.diyaudio.com/forums/pa-systems/212359-right-main-no-sound.html)

CumboJumbo

8th May 2012 07:30 PM

RIGHT MAIN no sound?

Hey, I have a LTO 12 channel mixer and the right main mix out isnt working. The left out gets sound but the right isnt working for some reason. Just want to know if theres something im not checking. Not panned, everything is normalized on the board, theres not even a crackle when I check the cable it just seems to be dead. Quick fix? Or **** *** out?

Enzo

8th May 2012 11:04 PM

WHo knows? Troubleshoot it.

Separate main faders? Or one stereo fader? Is the fader - whichever type - getting signal at its top end? Is there signal at its wiper?

Look at the op amps in the main section. ANy with unwanted DC on an output pin? ANy getting hot?

Does that mixer have patch jacks for the master section? Like inserts? Does signal come and go through an insert OK?

CumboJumbo

9th May 2012 12:53 AM

One main fader google LTO 12 channel For a picture. I hooked it up to my powered pa speaker, the left would make sound the right would not. I tried 1/4 in and xlr with the same result

chrispenycate

11th May 2012 02:09 PM

Googled LTO, and got numerous mixers by Alto (with the first "A" filled in as a triangle) Could you give a serial number or something? Is this a powered mixer with effects, or have I landed on a completely wrong model?

I'm pretty certain it can be mended, but need a bit more information before starting a test procedure.

imix500

12th May 2012 12:31 AM

If it has main inserts, exercise the jacks with a 1/4" plug. They can be troublesome esspecialy in clubs or bars.

Enzo

12th May 2012 04:58 PM

Cumbo, you will have to go inside for this.

My first test inside would be to scope or otherwise monitor the main fader. Is signal getting to the top of both sides of it, and is signal coming out the wiper of both sides of it?

CumboJumbo

13th May 2012 06:15 AM

It has built in effects. I tried the 1/4 inch and nothing works with the right side. Left side fine right side nothing

chrispenycate

14th May 2012 07:01 PM

Does it have a) output equalisers, b) mix insert points (probably three pin jacks, but wired strangely) c) output metering d) headphone amps and e) a model number? (does it seem to you I'm groping in the dark a bit?)

If it's the Zephyr ZMX 124 (possibly) it has four subgroups which have inserts, so probably the main mix does too (the picture quality in the website I've accessed is disturbingly illegible) and it probably gives you a mode of operation bypassing the main outs. I assume the meter says there is nothing coming out of the right hand side too? And that the headphones only work in one ear? (yeah, I know, but it's worth checking before opening the thing up). If you don't have a 'scope, build a probe lead to a jack , and plug it into a guitar amp; it won't tell you much about the quality of the sound, but is good for checking whether it exists or not, and the manufacturers build the inputs difficult to blow up, having worked with guitarists before.

Hm, I've found a user manual for an L-12, with block diagram; is it that one?